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Monday, October 22, 2012

Where do silverspot butterflies lay their eggs?

Posted by: Alyse Kennamer, Zoo Corps intern

Oregon silverspot butterfly.
Photo by Ryan Hawk/Woodland Park Zoo.

This summer, I had the unforgettable opportunity to work with a threatened species, the Oregon silverspot butterfly. While I was working here, an amazing idea came to my head for a study that could help scientists better understand and protect this species. I wanted to observe a female butterfly, see where she lays her eggs, and how it’s done.

Observing butterfly behavior
in the silverspot lab at the zoo. Photo by Ryan Hawk/Woodland Park Zoo.

It all started at the beginning of the summer when I joined
the silverspot project as part of the zoo’s teen program, Zoo Corps. I joined
Zoo Corps in my sophomore year of high school, and am now enrolled in my first
year of college. In early spring, we got to pick from a list of about 10 areas
we wanted to work in at the zoo. Working in the lab where the zoo rears
silverspot caterpillars was my first choice. You would probably think it was
weird, why would a teenager want to spend her summer picking violet leaves and
washing dishes for caterpillars when she was surrounded by a bunch of different
animals? But I knew it would be interesting, and something I would end up
loving. I was right about that.

Butterfly eggs set up in
jars in preparation to overwinter at the
zoo, protected from the elements. Photo by Ryan Hawk/Woodland Park Zoo.

At the silverspot lab, it did indeed start with picking early
blue violet leaves—the caterpillars’ sole source of food—and doing the dishes. But
once I showed some initiative, I was able to do pupae processing, where we put
the chrysalis into a triangular folded paper towel, and give it an individual
number to send out to Oregon in an effort to rebuild the wild population. It
was a lot of tedious work, but I knew I was saving a threatened species, and
that was all that mattered.

In Mid-August, the silverspot team, consisting of myself, my
Zoo Corps partner Autumn Olson, zoo collection manager Erin Sullivan, and
zookeepers Lorre Myers and Diane Abbey, went down to Oregon for a release trip.
While we were there, we saw butterflies galore. They were everywhere, and it
was just so amazing. We even saw them mating, something Erin told us she had
never seen in the wild before. One of the volunteers from the Department of Fish
and Wildlife asked the question, “Where do the silverspots lay their eggs?” and
nobody knew the answer, because it hasn’t often been seen in the wild.

I flashed back to the beginning of summer when I was
starting my focus, when Autumn and I were told by our supervisor that she
wanted us to do a project revolving around the butterfly. So I turned to
Autumn, and whispered my idea to observe a female butterfly in the lab to see
where she would lay her eggs. She thought it was great. That night over dinner
we also got encouragement for the idea from Diane and Lorre, and then we knew
we’d just have to get it approved by Erin.

An Oregon silverspot
butterfly takes to a bloom on the Oregon coast. Photo by Rachel Gray/Woodland
Park Zoo.

After we got back from the release trip in Oregon, we talked
to Erin about it. She told us that it was a good idea, and even she wanted to
know the outcome. Since the silverspot is a threatened species, we had to go through a lot of different approvals, including from the Department of Fish and Wildlife. The zoo
receives butterflies into the lab in order to lay eggs, the basis for our conservation project, and each female has a target number of eggs we hope she will
lay. On occasion there are some overachievers who lay more than the target number, and Fish and Wildlife gave me approval to use one of these overachieving
butterflies for my project. The day we got the
approval by Fish and Wildlife was the day I started set-up. Unfortunately, my
focus partner Autumn couldn’t participate in the project because her school
schedule wouldn’t allow it.

Enmeshed terrarium I created
for the butterfly subjects of my study. Photo by Ryan Hawk/Woodland Park Zoo/

So it became my project. I set up a 20 gallon terrarium, and
put rocks at the bottom of it, and then I did about ten trips to horticulture
and filled a bucket up with soil to put into the terrarium. I put five early
blue violet leaves into the terrarium, along with two false dandelion plants.
After I did that, I built an upper part to the terrarium out of PVC pipe, so
that if she wanted to fly she could. I covered that with mesh and secured it.
After the terrarium was set up, I put my first female butterfly, whom I named
Willow, inside the terrarium.

Writing
down my observations at the lab. Photo by Ryan Hawk/Woodland Park Zoo.

Now that the project is set up, I come in about three times
a week, to work around my school schedule, and I watch and observe her actions.
I make sure she has enough sugar water, and enough water. I take pictures, and
some videos, just hoping, and waiting for the moment she lays an egg. Willow
recently died, but she did leave me with one egg, which she laid on a violet
leaf. This went with my hypothesis, which was that I believed the butterfly
would lay eggs on the violet leaves because that is what the caterpillars eat.
I have put the next butterfly, named Adunca, into the terrarium, and am
continuing to observe her, to see what she does, and if I can catch egg laying
on video.

I hope this study will shed light on the egg-laying habits
of this threatened species, knowledge that scientists can use to help protect habitat
needed for silverspot reproduction.

I am so proud of you Alyse and the work you have done with the Butterfly's. You saw a need for the Butterfly's and went for it , You started a special program went through all the proper channels and people and got approval You were the key that opened a door for a Butterfly that was threatened , You sat for hours watching them caring for them writing everything down , You were the Key Baby girl that has made a big difference in a beautiful butterfly's life and it's survival to our planet , You are an Amazing young Lady and I Love you !!! Love Mommy